The invention relates to a device according to the preamble of patent claim 1, as known from DE 197 28 069 C1.
The known device is used for measuring the intraocular pressure and comprises a foldable implant on which, outside the field of vision of the eye, there is a telemetry system having a pressure sensor and a transmitter device with coil. With the transmitter device, information corresponding to the sensor signals can be fed wirelessly to a receiver device arranged outside the eye. The received information is converted into reproducible data in an evaluation device connected to the receiver device.
In the known device, the telemetry system which can be implanted in the eye can have a data logger in which the measurement data delivered continuously from the pressure sensor can be stored and from which the measurement data can, when necessary, be retrieved for a limited time in transmit-receive mode.
The object of the invention is to make available a device of the type mentioned above which can be folded or rolled and has excellent receive and transmit quality.
According to the invention, this object is achieved by the characterizing features of patent claim 1, the subclaims defining advantageous developments of the invention.
In the invention, the coil is arranged flat on a foldable support, in particular a support film, in the form of a plurality of adjacent coil windings in one plane surface. The telemetry device containing the electronics and/or the sensor are preferably contained in at least one electronic module (chip) and likewise applied with electrical contact to the coil on the foldable support. This arrangement is embedded in a foldable biocompatible implant material, in particular of polyorganosiloxane, e.g. polydimethylsiloxane. Here, the implant material can be used not only as a covering for the transmitter device and telemetry device, but also as a transmission medium to the sensor for the physical quantity to be measured, which especially can be the intraocular pressure or the temperature in the eye. That is to say, in a preferred embodiment, the sensor is also surrounded by the biocompatible implant material. However, it is also possible to leave the sensor uncovered on a sensor surface, which is sensitive to the physical quantity to be measured or recorded, or in a defined sensor area. The physical quantity to be measured and present in the eye, for example the intraocular pressure or temperature, then acts directly on the sensor surface or this sensor area. For the physical quantity, it is also possible to use a transmission medium other than the implant material.
By means of the planar configuration of the coil with a plurality of mutually adjacent coil windings which preferably lies in a plane perpendicular to the optic axis of the eye or of the implant designed as intraocular lens, a high transmit and receive quality is obtained without impairing the foldability or rollability of the implant material. Moreover, the necessary compatibility with the eye is achieved for the whole device. In addition to one planar layer, it is also possible for a plurality of planar layers (planes) lying one above the other to be provided for the coil windings.
In a preferred manner, the implant is designed, as an intraocular lens, the telemetry device and the transmitter device with the coil being accommodated outside the optic lens part, in particular mainly in the area of the haptic part of the intraocular lens surrounding the optic part of the lens. For this purpose, the haptic part can have an annular area which surrounds the optic lens part and within which the planar arrangement of the coil windings is accommodated. The coil windings are preferably designed as planar electrical conductor tracks which are preferably made of precious metal, especially gold. The conductor tracks of the coil windings are produced on the support film using conventional planar technology, for example by metal deposition, in particular electrodeposition, as are known in microstructuring processes.
The implant can also be of annular design. The coil windings are then arranged on at least one of the ring surfaces. The annular implant is preferably fixed on the sulcus of the eye. The ring can be made partly of a hard material, in particular PMMA, and partly of a flexible material, in particular silicone. The implant is preferably covered with a biocompatible material, for example silicone rubber. The ring can also be made entirely of silicone, in which case a stabilizing haptic part made in particular of PMMA or of another rigid material is provided.
The support film is designed as a thin flexible and foldable film which ensures a good adhesion for the metal of the coil windings, and in particular the film material has dielectric properties and can be made of a suitable plastic, e.g. a polyimide.
On account of the high degree to which the device can be rolled or folded, it can be implanted in the eye without having to modify the usual techniques of minimally invasive surgery. In this way, microelectronic and sensoric components can be fitted in the eye for wireless energy and signal transmission, for example in the form of an artificial intraocular lens which is foldable. The intraocular lens unfolds after implantation.